U.S. patent application number 16/272750 was filed with the patent office on 2019-06-06 for heart sound and pulse waveform acquisition and analysis.
The applicant listed for this patent is CALIFORNIA INSTITUTE OF TECHNOLOGY. Invention is credited to Morteza Gharib, Niema Pahlevan, Derek Rinderknecht, Peyman Tavallali.
Application Number | 20190167131 16/272750 |
Document ID | / |
Family ID | 57609182 |
Filed Date | 2019-06-06 |
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United States Patent
Application |
20190167131 |
Kind Code |
A1 |
Rinderknecht; Derek ; et
al. |
June 6, 2019 |
HEART SOUND AND PULSE WAVEFORM ACQUISITION AND ANALYSIS
Abstract
Devices, systems, and methods are described for acquiring heart
sound timing content to enhance pulse waveform analysis.
Inventors: |
Rinderknecht; Derek;
(Arcadia, CA) ; Gharib; Morteza; (Altadena,
CA) ; Pahlevan; Niema; (Pasadena, CA) ;
Tavallali; Peyman; (Pasadena, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CALIFORNIA INSTITUTE OF TECHNOLOGY |
Pasadena |
CA |
US |
|
|
Family ID: |
57609182 |
Appl. No.: |
16/272750 |
Filed: |
February 11, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15199160 |
Jun 30, 2016 |
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16272750 |
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62187777 |
Jul 1, 2015 |
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62187772 |
Jul 1, 2015 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 5/02438 20130101;
A61B 5/6824 20130101; A61B 5/6833 20130101; A61B 5/6831 20130101;
A61B 2562/0204 20130101; A61B 5/6822 20130101; A61B 7/00 20130101;
A61B 7/04 20130101; A61B 5/02416 20130101; A61B 2562/0223 20130101;
A61B 5/6826 20130101 |
International
Class: |
A61B 5/024 20060101
A61B005/024; A61B 7/04 20060101 A61B007/04; A61B 7/00 20060101
A61B007/00 |
Claims
1. A band-based apparatus for heart sound and pulse waveform
acquisition, the apparatus comprising: an elongate band adapted to
encircle a human body part; a first sensor positioned along the
band and adapted to measure heart sound; and a second sensor
different from the first sensor, wherein the second sensor is
adapted to measure a pulse waveform.
2. The apparatus of claim 1, wherein the band is a wrist band and
the second sensor is configured as a finger sensor and connected to
the band by electrical leads.
3. The apparatus of claim 1, wherein the second sensor is also
positioned along the band.
4. The apparatus of claim 3, further comprising at least one
additional first sensor and at least one additional second
sensor.
5. The apparatus of claim 4, further comprising an inward-facing
bump adapted to stabilize position of the band.
6. The apparatus of claim 1, wherein the band is a finger band or a
neck band.
7. The apparatus of claim 1, further comprising: processing
circuitry communicatively coupled with the first and second
sensors; and a non-transitory memory on which is stored a plurality
of instructions that, when executed, cause the processing circuitry
to determine a Dicrotic Notch timing position for the pulse
waveform provided by the second sensor by superposition of the
heart sound provided by the first sensor and the pulse
waveform.
8. A patch-based apparatus for heart sound and pulse waveform
acquisition, the apparatus comprising: a body; an adhesive region
adapted to attach the body to a subject's skin; and at least one
sensor adapted to acquire heart sound and a pulse waveform.
9. The apparatus of claim 8, wherein the sensor is an optical
sensor.
10. The apparatus of claim 8, wherein the sensor is a
magnetoresitive sensor.
11. The apparatus of claim 8, further comprising: processing
circuitry communicatively coupled with the at least one sensor; and
a non-transitory memory on which is stored a plurality of
instructions that, when executed, cause the processing circuitry to
determine a Dicrotic Notch timing position for the pulse waveform
provided by the at least one sensor by superposition of the heart
sound provided by the at least one sensor and the pulse
waveform.
12. A method for heart sound and pulse waveform acquisition and
analysis, the method comprising: acquiring a pulse waveform at a
first location; acquiring heart sound at a second location; and
determining a Dicrotic Notch timing position for the pulse waveform
by superposition of the pulse waveform and the heart sound.
13. The method of claim 12, wherein the first location is selected
from a radial artery, brachial artery, a femoral artery, a carotid
artery, chest wall and a photoplethysmograph location.
14. The method of claim 12, wherein the second location is selected
from a radial artery, a brachial artery, a femoral artery, a
carotid artery and chest wall.
15. The method of claim 14, wherein the first location is different
from the second location.
16. The method of claim 12, further comprising: acquiring a pulse
waveform at a first location with at least one sensor; acquiring
heart sound at a second location with the at least one sensor; and
determining, with processing circuitry, a Dicrotic Notch timing
position for the pulse waveform by superposition of the pulse
waveform and the heart sound.
17. The method of claim 16, wherein the a first sensor is used to
acquire the pulse waveform and a different, second sensor is used
to acquire the heart sound.
18. The method of claim 12, performed with the apparatus described
in claim 2.
19. The method of claim 12, performed with the apparatus described
in claim 3.
20. The method of claim 12, performed with the apparatus described
in claim 4.
21-23. (canceled)
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This filing is a continuation of U.S. patent application
Ser. No. 15/199,160, filed Jun. 30, 2016, which claims the benefit
of and priority to U.S. Provisional Application No. 62/187,772,
filed Jul. 1, 2015 and U.S. Provisional Application No. 62/187,777,
filed Jul. 1, 2015, all of which are incorporated by reference
herein in their entireties for all purposes.
FIELD
[0002] Devices, systems, and methods are described for acquiring
heart sound timing content for pulse waveform and associated
analysis.
BACKGROUND
[0003] The field of noninvasive cardiovascular measurement
techniques is growing. In this regard, there is a growing need for
systems, devices, and methods capable of collecting a number of
noninvasive physiological signals. These signals can be used to
diagnose and even predict a number of physiological conditions,
such as disease conditions and conditions associated with a healthy
cardiovascular system. Sounds produced by the cardiac system can
also prove useful. The signature produced by the sounds of the
heart can be useful in the diagnosis of disease conditions.
[0004] In another context, heart sounds can be used to provide
timing information related to left ventricular ejection time,
spanning the contraction of the left ventricle and aortic valve
opening, to the closure of the aortic valve forming the Dicrotic
Notch (DN) of a pulse waveform. DN location (e.g., as understood in
terms of valve closure events and relating to the timing of systole
within a pulse waveform) can be critical to a number of pulse
waveform diagnostic methods. One such method is the Intrinsic
Frequency (IF) method described in U.S. Pat. No. 9,026,193
incorporated herein by reference in its entirety for all purposes.
There exists needs for systems, devices, and methods for acquiring
and/or using heart sound timing content to enhance pulse waveform
analysis.
SUMMARY
[0005] Example embodiments for obtaining heart sound timing content
and pulse waveforms are described. These embodiments can include a
sensor for pulse waveform acquisition and an additional pressure
sensitive device (e.g., a second sensor) for detecting so-called
heart sound. Pulse waveforms, which relate to pressure driven
expansion or blood flow resulting from the contraction of the heart
and subsequent systemic interactions, can be sensed and recorded a
number of ways. In one example, pulse waveform sensing is performed
optically with a Light Emitting Diode (LED) and photodetector
system. Examples of such systems are described in US Publication
No. 2015/0297105 and International Publication No. WO 2015/112512,
both of which are incorporated by reference herein in their
entireties for all purposes. Embodiments of the pressure-sensitive
heart sound detection device may include, but are not limited to, a
piezo accelerometer, an electromagnetic microphone, a
piezoresistive pressure sensor, an optical microphone and/or a
displacement sensor.
[0006] Notably, non-invasive peripheral measurements of pulse
waveform signals often lack many of the features (e.g., the time
period of cardiovascular ejection) that can reveal important
clinical information. In elderly patients (often the subgroup with
the highest need for continuous diagnostic monitoring), pulse
waveform features are often attenuated making the identification of
the DN tedious at best. Introducing the measurement of the heart
sound addresses this problem as further described below.
[0007] Even members of a younger population may have attenuated
waveform features relative to the requirements for IF analysis.
Such waveforms may, however, still contain valuable clinical
information. Combining a microphone to measure heart sounds enables
the use of many pulse waveform analysis algorithms.
[0008] The example embodiments may operate by first measuring a
pulse waveform and then measuring one or more heart sounds, or by
first measuring one or more heart sounds and then measuring a pulse
waveform. Likewise, simultaneous or synchronized measurement can be
performed in the example embodiments. The pulse waveform and heart
sound detection can be done with a single sensor or a number of
sensors.
[0009] The pulse waveform can be measured from a multitude of
locations including, but not limited to, the following: radial
artery, brachial artery, femoral artery, carotid artery, chest wall
or a photoplethysmograph (PPG) location such as in connection with
a finger, leg or elsewhere.
[0010] Using the start of the pulse wave and assuming the heart
rate has not changed substantially, the heart sound can also be
measured simultaneously or in close time proximity to the pulse
waveform measurement at any of following locations: radial artery,
brachial artery, femoral artery, carotid artery or chest wall. From
the heart sound recording, the start of the cardiac cycle from the
pulse waveform and the first heart sound (e.g., S1, that results
from mitral and tricuspid valve closure occurring at the beginning
of ventricular systole) can be used to align the waveforms, and DN
location (e.g., notch time) can be estimated. In other cases where
heart rates vary, the waveforms may be normalized with respect to
time and/or amplitude such that all waveforms span similar ranges
regardless of morphology.
[0011] An analog/digital stethoscope may be used to record the
heart sounds on the chest or on the carotid artery. This timing
information can be used to infer timing on a brachial pulse
waveform, radial pulse waveform, or PPG waveform. The combinations
of locations where this technique can be applied are not limited to
those described above. A table below details a more extensive, but
still non exhaustive list.
[0012] In some cases, the heart sounds may be recorded in the same
location, area or vicinity of the pulse waveform. Likewise, the
heart sounds may be recorded simultaneously with the pulse
waveform. In one example, a wrist worn device is used where the
pulse waveform is recorded from a PPG and a small microphone
located on or within the band or watch itself is used to record the
heart sound for determining timing information for the
waveform.
[0013] The sensors may be integrated into a watch body or into a
band (of a watch or otherwise). One wrist-band embodiment includes
a multitude of sensors which may allow freedom of movement. In
another wrist-band embodiment, a microphone and a pulse waveform
sensor are located over the radial and ulnar arteries (or vice
versa) with positioning maintained securely by the band. Either
way, sounds and pulse waveform are recorded simultaneously and may
be broadcast wirelessly.
[0014] The detection (of heart sound and/or pulse waveform) may be
purely optical interaction with the skin or may be combined with a
membrane (e.g., as further described in US Publication No.
2015/0297105 and International Publication No. WO 2015/112512
referenced above, and also described in U.S. Pat. No. 5,363,855,
which is incorporated herein by reference in its entirety for all
purposes). The membrane can serve to maintain similar photodetector
response in a number of situations of changing light or optical
spectrum.
[0015] Such a membrane may also possess certain features such as
nodes, bumps, or curvature to assist in the collection of data. In
one such embodiment, the membrane is formed to match the curvature
of the wrist as well as provide more intimate contact between the
membrane and the skin overlying the artery.
[0016] Of the band-based platform examples, one example is a wrist
worn watch that combines pulse waveform detection and heart sound
detection into a wearable platform. As for the "watch" description,
this terminology may indicate function and/or form factor. Namely,
the subject systems or devices may offer the full function of a
watch, even a so-called "smartwatch" (e.g., as provided by Apple,
Samsung, or others) together with the subject features in a
wrist-worn package. Alternatively, the subject features are
provided without a time-telling display and/or other associated
features.
[0017] In other examples, the band-based device may instead be worn
on the neck to measure information from the carotid artery. Another
example is configured to substantially encircle a portion of a
subject's appendage (e.g., the upper arm, waist, or thigh, etc.),
or to encircle the entire appendage. As used herein, the term
"encircle" and its variants do not require the structure to form a
geometric circle around the body portion and, in fact, any shape
can be used to extend around the body portion. Likewise, the term
"surround" does not require the body portion to be surrounded in
all directions, as such would be inconsistent with the usage of
that term herein. Instead the terms "encircle" and "surround" are
used in the same sense that a watch or a wrist-worn activity
monitor encircles and surrounds the arm or wrist. Still other
options are within the scope of this disclosure.
[0018] To encircle or surround the body portion, the band may be
provided to the wearer (e.g., as provided in packaging) in an
elongate shape or form and be closed to define the surrounding
shape, e.g., a circle, oval, etc. This may be accomplished with one
or more snaps, buckles, VELCRO elements, magnetic clasps or other
mechanisms known in the art. Alternatively, the band may be
manufactured and provided to the wearer in the surrounding curved
shape (with or without a break) and may include diameter adjustment
or adjustable features (e.g., elastic, air bladder or as in a
spring and linkage or other type of expansion watch band).
[0019] An adhesive-type patch (e.g., similar to an ECG or EKG
electrode patch) offers another form factor suitable for measuring
heart sound and the pulse waveform. In connection with such a
device (or otherwise), the pulse waveform and/or heart sound
detection may also be done electromagnetically or via
magnetoresistive materials.
[0020] Any of these devices and/or systems may have Bluetooth
connection capability or otherwise be wireless. In certain
situations, the hardware and/or associated methodology may be used
for clinical monitoring in health care establishments (e.g.,
hospital departments like an operating room (OR), or intensive care
unit (ICU)). In other cases, such sensors may be useful for
ambulatory monitoring.
[0021] The subject devices or systems, kits in which they are
included (with and without assembly), methods of use and
manufacture (including assembly of the constituent components) are
all within the scope of the present disclosure. Some aspects of the
same are described above and more detailed discussion is presented
in connection with the figures below.
[0022] Various systems, devices, methods, features and advantages
of the subject matter described herein will be or will become
apparent to one with skill in the art upon examination of the
following figures and Detailed Description. It is intended that all
such systems, devices, methods, features and advantages be included
within this description, be within the scope of the subject matter
described herein and be protected or protectable by the
accompanying claims. In no way should the features of the example
embodiments be construed as limiting the appended claims, absent
express recitation of those features in the claims.
BRIEF DESCRIPTION OF THE FIGURES
[0023] The details of the subject matter set forth herein, both as
to its structure and operation, may be apparent by study of the
accompanying figures, in which like reference numerals refer to
like parts. The components in the figures are not necessarily to
scale, emphasis instead being placed upon illustrating the
principles of the subject matter. Moreover, all illustrations are
intended to convey concepts, where relative sizes, shapes and other
detailed attributes may be illustrated schematically rather than
literally or precisely.
[0024] FIG. 1A is a chart showing an example of each of a pulse
waveform and heart sound from a young (e.g., up to about 30 years
in age) human subject.
[0025] FIG. 1B is a chart showing an example of each of a pulse
waveform and heart sound for an old (e.g., over about 65 years in
age) subject.
[0026] FIG. 2 is a diagram presenting example locations for
acquiring pulse waveform and heart sounds and providing a
superimposed system output.
[0027] FIGS. 3A and 3B depict an example of an attenuated pulse
waveform signal, and an example of a heart sound signal,
respectively, each taken over more than one cycle in time with a
large Y scale.
[0028] FIG. 4 is a diagram of an example embodiment of a system in
which heart sound and a pulse waveform are recorded in separate
locations.
[0029] FIG. 5 is a diagram of another example embodiment of a
system in which heart sound and a pulse waveform are recorded in
separate locations in connection with a first band-based
embodiment.
[0030] FIG. 6 is a diagram of another example embodiment of a
band-based system, together with combined heart sound and pulse
waveform information recorded therewith.
[0031] FIG. 7 is an illustration of an example embodiment of a
band-based system including additional sensors.
[0032] FIG. 8A is an illustration of an example embodiment of a
band-based system with a single sensor location. FIG. 8B is a
cross-sectional view of the embodiment in FIG. 8A taken along line
8B-8B.
[0033] FIG. 9 is an illustration of an example embodiment of a
finger-worn band-based system.
[0034] FIG. 10 is an illustration of an example embodiment of a
leg-worn band-based system.
[0035] FIG. 11 is an illustration of an example embodiment of a
neck-worn band-based system.
[0036] FIG. 12 is an illustration of an example embodiment of a
sensor patch based system.
[0037] FIGS. 13A and 13B are cross-sectional views of the
embodiment of FIG. 12, taken along line 13-13, showing alternative
sensor architecture embodiments.
DETAILED DESCRIPTION
[0038] Before the present subject matter is described in detail, it
is to be understood that this disclosure is not limited to the
particular embodiments described, as such may, of course, vary. It
is also to be understood that the terminology used herein is for
the purpose of describing particular embodiments only, and is not
intended to be limiting, since the scope of the present disclosure
will be limited only by the appended claims.
[0039] It should be noted that all features, elements, components,
functions, acts and steps described with respect to any embodiment
provided herein are intended to be freely combinable and
substitutable with those from any other embodiment. If a certain
feature, element, component, function, act or step is described
with respect to only one embodiment, then it should be understood
that that feature, element, component, function, act or step can be
used with every other embodiment described herein unless explicitly
stated otherwise. This paragraph therefore serves as antecedent
basis and written support for the introduction of claims, at any
time, that combine features, elements, components, functions, acts
and steps from different embodiments, or that substitute features,
elements, components, functions, acts and steps from one embodiment
with those of another, even if the following description does not
explicitly state, in a particular instance, that such combinations
or substitutions are possible. It is explicitly acknowledged that
express recitation of every possible combination and substitution
is overly burdensome, especially given that the permissibility of
each and every such combination and substitution will be readily
recognized by those of ordinary skill in the art.
[0040] Various example embodiments are described below. Reference
is made to these examples in a non-limiting sense. They are
provided to illustrate more broadly applicable aspects of inventive
aspects. Various changes may be made to the embodiments described
and equivalents may be substituted without departing from their
true spirit and scope. In addition, many modifications may be made
to adapt a particular situation, material, composition of matter,
process, process act(s) or step(s) to the objective(s), spirit or
scope of the claims made herein.
[0041] As referenced above, the example embodiments described
herein can be used to measure heart sound and a pulse waveform at
various measurement locations. A non-exhaustive list of examples
(indicated by an X) are set forth below in TABLE 1.
TABLE-US-00001 TABLE 1 Location of Waveform Recording Dorsalis
Carotid Brachial Radial Femoral pedis Posterior Finger (Right
(Right (Right (Right Popliteal (Right Temporal Tibial (Right
Invasive or or or or (Right or or (Right or (Right or or Invasive
Hemodynamic Left) Left) Left) Left) Left) Left) Left) Left) Left)
Catheter Sensor Location Carotid (Right or x x x x x x x x x x of
Left) Heart Brachial (Right or x x x x x x x x x x Sound Left)
Recording Radial (Right or x x x x x x x x x x Left) Femoral (Right
or x x x x x x x x x x Left) Popliteal (Right x x x x x x x x x x
or Left) Dorsalis pedis x x x x x x x x x x (Right or Left)
Temporal (Right x x x x x x x x x x or Left) Posterior Tibial x x x
x x x x x x x (Right or Left) Finger (Right or x x x x x x x x x x
Left) Invasive Catheter x x x x x x x x x x Invasive x x x x x x x
x x x Hemodynamic Sensor
The example embodiments described herein can be adapted for use
with any of these locations (and others) and, to the extent a
particular combination of hardware and location is not explicitly
described herein, then the implementation of that embodiment can be
accomplished by one of ordinary skill in the art after reading the
present application. It is noted that some of these embodiments can
be implemented with conventional "off-the-shelf" hardware (e.g., an
invasive catheter or a hemodynamic sensor).
[0042] FIGS. 1A and 1B are illustrative with regard to the signals
acquired and employed in a superposition method. In FIG. 1A, an
example of a pulse waveform 100 is shown. It includes a
well-defined or discernable DN.
[0043] FIG. 1A also shows a recorded heart sound signal 110 with
first and second heart sounds (S1 and S2). Here, S1 aligns with the
beginning of the pulse waveform. The beginning location of S2 along
time axis t (as indicated by the dashed line) aligns with the
DN.
[0044] FIG. 1B shows an example of an attenuated pulse waveform
104. A zone or region of uncertainty 106 exists over which the DN
should be located. Using a recorded heart sound signal 112, an
estimate of DN location can be determined at the time position
indicated by the dashed line. With DN timing known relative to
waveform 104, even an attenuated signal can be analyzed with IF
and/or other analytical techniques. Such an analysis would not be
possible with the pulse waveform alone (e.g., without the timing
information provided by the heart sounds signal).
[0045] FIG. 2 is further illustrative of the method. Functional
block 120 represents hardware to acquire (e.g., sense and record) a
pulse pressure waveform (an attenuated example 104 in this case)
over one or more cycles at any of the locations of TABLE 1 (or
others). Functional block 122 represents use of (the same or
different) hardware to acquire heart sounds S1 and S2, again, at
any of a selection of the example locations listed.
[0046] Using computer processing circuitry, optionally in real
time, the signals are superimposed by a process 124 to yield a
result that may be electronically stored and subsequently analyzed,
displayed (e.g., as in composite graph 130) or otherwise handled.
In this graph, S1 and pressure waveform timing start is coincident
along line 132. DN timing (as determined in the attenuated signal
112) along line 134.
[0047] FIGS. 3A and 3B depict an attenuated pulse waveform signal
104, and a heart sound signal 112, respectively, each taken over
more than one cycle in time with a large Y axis scale. FIGS. 3A and
3B are helpful in illustrating example embodiments of methods of
using the start of the cardiac cycle from the pulse waveform and S1
from the heart sound recording to align the waveforms to estimate
Dicrotic Notch (DN) time. In these embodiments, if the heart rate
when the pulse waveform is recorded (HR.sub.PW) is equal to or
about equal to the heart rate when the heart sounds are recorded
(HR.sub.S) or these signals are recorded simultaneously then
t.sub.0=t.sub.1 or t.sub.0.noteq.t.sub.1 then
t.sub.n=t.sub.0+(t.sub.2-t.sub.1) as shown. By this calculation
(optionally referred to as superposition of the waveforms), t.sub.n
provides an estimate of DN timing location. With this position,
waveform 110 can then be analyzed using IF methodology. In other
words, the start of the cardiac cycle from the pulse waveform and
S1 from the heart sound can be used to align the waveforms so that
DN time can be estimated.
[0048] As shown in FIG. 4, functional modules 120 and 124 may be
incorporated in existing hardware such as a digital blood pressure
cuff 140 and a digital stethoscope 142. A separate hardware piece
(such as a smart phone, a general purpose computer or other
hardware) 144 may incorporate function block 124. In any case,
signals corresponding to a pulse waveform 104 (here, the brachial
waveform of a subject 10) and heart sounds 112 (here, recorded at
the chest wall 12 of the subject) are received and combined or
otherwise superimposed to provide composite timing and DN
information, optionally, as shown as graph 130. Otherwise, the
signal data and systolic and diastolic intervals may be simply
stored electronically in a spreadsheet or other means for
subsequent IF calculation purposes.
[0049] In any case, hardware pictured in FIG. 4 and associated
methodology contemplates acquiring and recording pulse waveform and
heart sound signals at different locations with different sensors
and combining or otherwise superimposing their information.
[0050] Another approach to utilizing this approach is shown in FIG.
5. Here, system 150 includes a band 152 located around the wrist 14
of a user incorporates or carries a sensor 154 positioned to
measure heart sounds at the subject's radial artery 16. A PPG or
pulse oximeter 156 is set over the subject's finger 16 to measure
the pulse waveform. The PPG 156 is optionally connected by an
electrical lead 1568 to band 150 to operate much like the system
shown in in FIG. 4. In this regard, the band may further
incorporate electronic hardware 144 to perform function 124.
[0051] FIG. 5 shows another band-based embodiment 160, which is
wireless (see signal icon). On-board electronics may communicate a
composite graph or combined signal 130 as indicated by the arrow in
the figure. Alternatively, pulse and heart sound signals may be
communicated wirelessly to external hardware for superposition
and/or other (e.g., IF calculation) processing.
[0052] Regardless, embodiment 160 includes a band 150 in which at
least one pair of sensors are included. The paired sensor may
include a microphone 162 for sensing heart sound and an optical
sensor 164 for detecting the pulse waveform. One such pair of
sensors may be located so that it picks-up a signal from a
subject's radial artery 14, with another pair of the sensors
located to pick-up a signal from the ulnar artery 18.
Alternatively, the sensor pair (162 and 164) may be broken-up so
that one sensor (162 or 164) is positioned (by the band) over the
radial artery and the other sensor (164 or 162) over the ulnar
artery. When two pairs of sensors are used as illustrated, signal
acquisition redundancy is provided. The sensors may be multiplexed
or sampled sequentially. Different orientations or array grids may
be used as shown in 162 and 164 to optimize signal fidelity and
signal-to-noise ratio.
[0053] In the band-based embodiment 170 shown in FIG. 7, the sensor
pairs are multiplexed, with the number of sensors multiplied to
make sensing further redundant. As such, the band is allowed
freedom of motion while still ensuring good signal acquisition.
[0054] In contrast, a single sensor embodiment 180 in shown in
FIGS. 8A and 8B. Here, the sensor 182 set within a cell or pocket
184 of the band may be purely optical, having interaction with the
skin or it may operate with a membrane 186. As shown, the membrane
includes a raised region, protuberance or bump 186 to match the
curvature of the wrist (helping hold or "lock" the band in
position) as well as to provide more intimate contact between the
membrane and the skin overlying the artery. When the membrane is a
plastic film, the geometry of the bump may be provided by
thermoforming. Other options are possible as well such as molding
using soft materials, machining or techniques such as three
dimensional (3D) printing.
[0055] FIG. 9 shows a band-based embodiment 190 in the form of a
ring, set upon a user's finger 16. FIG. 10 shows a band-based
embodiment 200 over a subject's leg 20 to sense at or over the left
femoral artery 22. This band 150 is configured and/or positioned
like a bridal garter. Alternatively (or additionally) the right
femoral artery 24 can have device 200 set there for sensing.
[0056] FIG. 11 shows a band-based device 210 configured to be worn
on the neck 26 to measure on the right and or left carotid arteries
(28 and 30, respectively). Here, (again located on the neck 26 of a
subject) a sensor device 220 may take the form of an adhesive patch
as illustrated in FIG. 12. The patch includes a housing 222 having
a sensor region 224 and an underlying adhesive region 226. The
adhesive may be in the form of an applied patch or be otherwise
provided. It may be protected by a peel ply (not shown) prior to
its preparation for use. The membrane and/or the adhesive portion
of the patch may also be disposable allowing the user to retain the
sensor, signal conditioning hardware, and data transmission
hardware, but replace elements in contact with the skin to maintain
sterility and cleanliness.
[0057] In version 220A shown in FIG. 13A, an optical sensor 230 is
provided to work in association with membrane 232. Electronics 234
may be included in space of body 236 supporting or above the region
of sensor 230. As shown, the adhesive element 224 may be in the
form or a ring surrounding the membrane 232 (where this "ring" may
be round, rectangular or otherwise shaped). Alternatively, the
membrane may be lightly coated with adhesive itself.
[0058] In any case, with the patch temporarily adhered to the skin
32 of a subject, the pulse waveform and sounds carried within an
artery (e.g., carotid 28 or 30) can be acquired by a single sensor.
Alternatively, different sensors may be provided as per above. The
signals may be processed on-board by the electronics and
communicated wirelessly (as indicated), or simply recorded and
communicated wirelessly as described above.
[0059] FIG. 13B shows an embodiment version 220B in which the
membrane 232 is magnetically poled (see the North (N) and South (S)
pole indication (which, of course, may be reversed) and a
magnetoresistive or hall effect sensor 238, the material of which
changes voltage in response to the displacement of the membrane.
Notably, the patch-based embodiment 220 (irrespective of its inner
workings per variation 220A or 220B) may be placed on the neck 26
as described above, on or at the wrist 14 or otherwise.
[0060] Additional Variations
[0061] The band may comprise any conventional material including
metals, rubbers, plastics, and/or so-called "smart" materials that
can be controlled via external stimuli. Likewise, other system
components may be constructed with commonly available components
and/or materials as will be appreciated by those with skill in the
art.
[0062] In addition to the embodiments disclosed already, still more
variations are within the scope of this description. For example,
the various illustrative methods or processes described in
connection with the embodiments herein may be implemented or
performed with a general purpose processor, a Digital Signal
Processor (DSP), an Application Specific Integrated Circuit (ASIC),
a Field Programmable Gate Array (FPGA) or other programmable logic
device, discrete gate or transistor logic, discrete hardware
components, or any combination thereof designed to perform the
functions described herein.
[0063] A general purpose processor may be a microprocessor, but in
the alternative, the processor may be any conventional processor,
controller, microcontroller, or state machine. The processor can be
part of a computer system that also has a user interface port that
communicates with a user interface, and which receives commands
entered by a user, has at least one memory (e.g., hard drive or
other comparable storage, and random access memory) that stores
electronic information including a program that operates under
control of the processor and with communication via the user
interface port, and a video output that produces its output via any
kind of video output format, e.g., VGA, DVI, HDMI, DisplayPort, or
any other form.
[0064] A processor may also be implemented as a combination of
computing devices, e.g., a combination of a DSP and a
microprocessor, a plurality of microprocessors, one or more
microprocessors in conjunction with a DSP core, or any other such
configuration. These devices may also be used to select values for
devices as described herein. The camera may be a digital camera of
any type including those using CMOS, CCD or other digital image
capture technology.
[0065] The steps of a method or algorithm described in connection
with the embodiments disclosed herein may be embodied directly in
hardware, in a software module executed by a processor, or in a
combination of the two. A software module may reside in Random
Access Memory (RAM), flash memory, Read Only Memory (ROM),
Electrically Programmable ROM (EPROM), Electrically Erasable
Programmable ROM (EEPROM), registers, hard disk, a removable disk,
a CD-ROM, or any other form of storage medium known in the art. An
exemplary storage medium is coupled to the processor such that the
processor can read information from, and write information to, the
storage medium. In the alternative, the storage medium may be
integral to the processor. The processor and the storage medium may
reside in an ASIC. The ASIC may reside in a user terminal. In the
alternative, the processor and the storage medium may reside as
discrete components in a user terminal.
[0066] In one or more exemplary embodiments, the functions
described may be implemented in hardware, software, firmware, or
any combination thereof. If implemented in software, the functions
may be stored on, transmitted over or resulting
analysis/calculation data output as one or more instructions, code
or other information on a computer-readable medium.
Computer-readable media includes both computer storage media and
communication media including any medium that facilitates transfer
of a computer program from one place to another. A storage media
may be any available non-transitory media that can be accessed by a
computer. By way of example, and not limitation, such
computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or
other optical disk storage, magnetic disk storage or other magnetic
storage devices, or any other medium that can be used to carry or
store desired program code in the form of instructions or data
structures and that can be accessed by a computer. The memory
storage can also be rotating magnetic hard disk drives, optical
disk drives, or flash memory based storage drives or other such
solid state, magnetic, or optical storage devices. Disk and disc,
as used herein, includes compact disc (CD), laser disc, optical
disc, digital versatile disc (DVD), floppy disk and Blu-ray disc
where disks usually reproduce data magnetically, while discs
reproduce data optically with lasers. Combinations of the above
should also be included within the scope of computer-readable
media.
[0067] To the extent the embodiments disclosed herein include or
operate in association with memory, storage, and/or computer
readable media, then that memory, storage, and/or computer readable
media are intended to be non-transitory. Accordingly, to the extent
that memory, storage, and/or computer readable media are covered by
one or more claims, then that memory, storage, and/or computer
readable media is only non-transitory.
[0068] Operations as described herein can be carried out on or over
a website or network. The website can be operated on a server
computer or operated locally, e.g., by being downloaded to the
client computer, or operated via a server farm. The website can be
accessed over a mobile phone or a PDA, or on any other client. The
website can use HTML code in any form, e.g., MHTML, or XML, and via
any form such as cascading style sheets ("CSS") or other.
[0069] Moreover, no limitations from the specification are intended
to be read into any claims, unless those limitations are expressly
included in the claims. The computers described herein may be any
kind of computer, either general purpose, or some specific purpose
computer such as a workstation. The programs may be written in C,
or Java, Brew or any other programming language. The programs may
be resident on a storage medium, e.g., such as those already
described. The programs may also be run over a network, for
example, with a server or other machine sending signals to the
local machine, which allows the local machine to carry out the
operations described herein.
[0070] As used herein and in the appended claims, the singular
forms "a", "an", and "the" include plural referents unless the
context clearly dictates otherwise. In other words, use of the
articles allow for "at least one" of the subject items in the
description above as well as the claims below. The claims may
exclude any optional element. As such, this statement is intended
to serve as antecedent basis for use of such exclusive terminology
as "solely," "only" and the like in connection with the recitation
of claim elements, or use of a "negative" limitation.
[0071] Without the use of such exclusive terminology, the term
"comprising" in the claims shall allow for the inclusion of any
additional element irrespective of whether a given number of
elements are enumerated in the claim, or the addition of a feature
could be regarded as transforming the nature of an element set
forth in the claims.
[0072] The publications discussed herein are provided solely for
their disclosure prior to the filing date of the present
application. Nothing herein is to be construed as an admission that
the present disclosure is not entitled to antedate such publication
by virtue of prior disclosure. Further, the dates of publication
provided may be different from the actual publication dates which
may need to be independently confirmed.
[0073] The subject matter described herein and in the accompanying
figures is done so with sufficient detail and clarity to permit the
inclusion of claims, at any time, in means-plus-function format
pursuant to 35 U.S.C. section 112, part (f). However, a claim is to
be interpreted as invoking this means-plus-function format only if
the phrase "means for" is explicitly recited in that claim.
[0074] While the embodiments are susceptible to various
modifications and alternative forms, specific examples thereof have
been shown in the drawings and are herein described in detail. It
should be understood, however, that these embodiments are not to be
limited to the particular form disclosed, but to the contrary,
these embodiments are to cover all modifications, equivalents, and
alternatives falling within the spirit of the disclosure.
Furthermore, any features, functions, steps, or elements of the
embodiments may be recited in or added to the claims, as well as
negative limitations that define the inventive scope of the claims
by features, functions, steps, or elements that are not within that
scope.
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